RT patch breaks X86_64 build

[Parag Warudkar <kernel-stuff@comcast.net>]

Ingo,

Realtime patch breaks the x86_64 build -

CC      arch/x86_64/kernel/mce.o
In file included from arch/x86_64/kernel/mce.c:17:
include/linux/fs.h: In function `lock_super':
include/linux/fs.h:828: warning: implicit declaration of function `down'
include/linux/fs.h: In function `unlock_super':
include/linux/fs.h:833: warning: implicit declaration of function `up'
arch/x86_64/kernel/mce.c: In function `mce_read':
arch/x86_64/kernel/mce.c:383: warning: type defaults to `int' in declaration 
of `DECLARE_MUTEX'
arch/x86_64/kernel/mce.c:383: warning: parameter names (without types) in 
function declaration
arch/x86_64/kernel/mce.c:392: error: `mce_read_sem' undeclared (first use in 
this function)
arch/x86_64/kernel/mce.c:392: error: (Each undeclared identifier is reported 
only once
arch/x86_64/kernel/mce.c:392: error: for each function it appears in.)
make[1]: *** [arch/x86_64/kernel/mce.o] Error 1
make: *** [arch/x86_64/kernel] Error 2

Parag